Some years ago it was shown by Shafrin and her co-workers that a field of close-packed trifluoromethyl groups has an extremely low critical surface tension of only 6 dynes/cm. This was surprising in view of the fact that chains of difluoromethylene groups, as found in polytetrafluoroethylene, have a critical surface tension of 18 dynes/cm. E. G. Shafrin et al., "Constitutive Relations In The Wetting Of Low Energy Surfaces And The Theory Of The Retraction Method Of Preparing Monolayers," 64 J.Phys.Chem. 519-524 (1960).
Various attempts have been made to produce acrylic polymers having trifluoromethyl groups. U.S. Pat. No. 3,544,535 (Gilbert et al.) describes the production of 2-(pentafluorophenyl)hexafluoroisopropanol by the reaction of pentafluorophenyl magnesium bromide with hexafluoroacetone in an ether solvent followed by hydrolysis of the reaction product. The acrylate and methacrylate esters are prepared by reacting 2-(pentafluorophenol)hexafluoroisopropanol with an acrylic compound in an organic solvent and in the presence of an adjuvant such as triethylamine. Polymerization of the acrylate and methacrylate esters is accomplished in the presence of a catalyst such as potassium persulfate or benzoyl peroxide. The polymers are said to have hydrophobic properties and to be useful as textile impregnants.
U.S. Pat. Nos. 4,356,296 and 4,452,998 to Griffith et al. describe the synthesis and polymerization of a fluorinated diacrylate ester monomer having the formula: ##STR2## wherein R is --CF.sub.3 or --C.sub.2 F.sub.5, R' is --H or --CH.sub.3, R" is --H or --(CF.sub.2).sub.n F, and n is an integer of from 1 to 10. The monomer is prepared by reacting a fluoroaromatic diol and acryloyl chloride in a highly fluorinated solvent and in the presence of an acid acceptor. The monomer forms a hydrophobic cross-linked thermoset polymer having dental and biomedical applications. See also U.S. Pat. No. 4,284,747 (Griffith et al.).
U.S. Pat. No. 3,407,183 (Farah et al.) concerns the production of the acrylate and methacrylate esters of 1,3-bis (heptafluoroisopropyl)benzenesulfonyl-(N-alkyl,N-2-hydroxyethyl) amides. The polymers of these esters are said to be useful for treating fabrics to render them oil repellant.
U.S. Pat. No. 3,304,334 (Jones) describes the production of tris-1,3,5-(2-hydroxyhexafluoro-2-propyl) benzene by reacting bis-1,3-(2-hydroxyhexafluoro-2-propyl) benzene with hexafluoroacetone in the presence of BF.sub.3 and at a pressure of 20 kilobars. The product was found to be hygroscopic and was said to be useful as a reactant in the preparation of polyethers, polyesters, polyamides, and polyurethanes, as plastics, fibers, coatings, elastomers, and foams, and because of its tri-functionality, as a cross-linking agent when used in small amounts in the preparation of polymers. When reacted with 2,4-toluene diisocyanate a polymer having high electrical resistivity and good dielectric properties is said to be produced.